The present embodiments relate to digital subscriber line (“DSL”) technology, and are more particularly directed to a DSL modem operable to efficiently connect to DSL services in existing telephone service connectors.
The exchange of digital information between remotely located computers is now a pervasive part of modem computing and occurs in all sorts of computer contexts including business, education, and personal use. Such uses by all current predictions appear to be even more desirable in the future. Video on demand (“VOD”) is one area which has for some time driven the advancement of technology in this area. More recently, the rapid increase in use and popularity of the Global Internet hereafter, the “Internet”) has perhaps surpassed the excitement created by VOD.
One type of technology arising from the above and continuing to evolve is referred to in the art as digital subscriber line or DSL. DSL is a public network technology that delivers relatively high bandwidth over conventional telephone company copper wiring at limited distances. DSL has been further separated into several different categories, where the differing DSL categories are currently developing, some at different rates than others. This evolution prevents an absolute definition of certain DSL categories, but some observations may be made at the current time. Generally with respect to the various DSL technology categories, each differs in some respects while each also shares some similarities. As to differences of the DSL categories, they may diverge in one or more of the expected data transfer rate, the medium type and length over which data are communicated, and the scheme for encoding and decoding data for communication. As to the similarities of the DSL technologies, generally speaking each DSL system is provisioned into modem pairs. One modem of the modem pair is located at a customer site. The other modem of the modem pair is located at the site of an owner, or controller, of a twisted conductor pair network. Currently, the most evident owner or controller is a telephone company central office. Within the telephone company system, its modem is connected to communicate with some type of network, often referred to as a backbone network. The backbone network is further coupled in a network manner to provide other communication paths to and from the backbone network. Given its network nature, the backbone network may further communicate with other information sources and, most notably under current technology, with the Internet. Thus, information accessible to the backbone network, such as Internet information, may be communicated between the central office DSL modem and a customer site with its own compatible DSL modem. Within this general system, it is also anticipated that data rates between DSL modems may be far greater than current voice modem rates. Indeed, current DSL systems being tested or projected range in rates on the order of 500 Kbps to 18 Mbps, or even faster. The higher rates for some DSL systems are only for so-called downstream communications, that is, from the central office to the customer site; thus, for those systems, communication in the other direction (i.e., upstream from the customer site to the central office) is generally at a rate considerably lower than the downstream rate. Lastly, note that most DSL technologies do not use the whole bandwidth of the twisted wire pair, and they often reserve low bandwidth for a voice channel. As a result, while a line is being used by a DSL system, the same line may concurrently communicate a voice conversation as well.
Briefly looking at perhaps the most publicized DSL technology currently being developed, it is referred to as Asymmetric Digital Subscriber Line, or “ADSL.” ADSL has been standardized by ANSI as seen by its T1.413 standard. However, even given that standard, there continues to be debate and competition as to whether devices complying with the standard provide promise for future wide scale use, and indeed whether the standard requires revision. For example, the standard currently contemplates a modulation technology called Discrete Multitone (DMT) for the transmission of high speed data, but more recently it has been urged that the standard further include an alternative data transmission technique referred to as carrierless amplitude/phase modulation (CAP). In any event, given the state of the art discussion of ADSL systems, it is contemplated that they will communicate over a single copper twisted wire pair, and provide downstream rates on the order of 1.5 Mbps to 9 Mbps, while upstream bandwidth will range from 16 kbps to 1 Mbps. Along with Internet access, telephone companies are considering delivering remote local area network (“LAN”) access and VOD services via ADSL.
As to other DSL categories being developed, they include High-Bit-Rate Digital Subscriber Line (“HDSL”), Symmetrical Digital Subscriber Line (“SDSL”), and Very-high-data-rate Digital Subscriber Line (“VDSL”). HDSL, unlike ADSL as described above, has a symmetric data transfer rate, that is, it communicates at the same speed in both the upstream and downstream directions. Current perceived speeds are on the order of 1.544 Mbps of bandwidth, but require two copper twisted wire pairs. HDSL's operating range is more limited than that of ADSL, and is currently considered to be effective at distances of approximately 12,000 feet. Beyond such a distance, HDSL communication requires signal repeaters to extend the service. SDSL delivers a comparable speed and also a symmetric data transfer as compared to HDSL, but achieves these results with a single copper twisted wire pair. However, the operating range of an SDSL system is limited to approximately 10,000 feet. Lastly, VDSL provides asymmetric data transfer rates, but anticipates much higher speeds than those competing DSL technologies described above. Currently, rates over a single twisted copper pair on the order of 13 Mbps to 52 Mpbs downstream, and 1.5 Mbps to 2.3 Mbps upstream, are contemplated. Note, however, that such rates are expected to operate only over a range of 1,000 to 4,500 feet.
Having introduced DSL technology, attention is now directed to the implementation of that technology at the consumer level. Under the current and typical scenario, when a consumer wants DSL capability in his or her computer, the consumer contacts a DSL provider (e.g., the local telephone company). The DSL provider then sends a representative to the location specified by the consumer and connects a DSL modem to the consumer's computer. More particularly under contemporary implementations, an external DSL modem is connected to the consumer's computer, such as by coupling the external DSL modem to a network interface card (“NIC”) located internally within the computer. Alternative couplings also may be used or are currently being developed (e.g., use of the Universal Serial Bus (“USB”)). The DSL modem is also then coupled to the telephone wiring in the location of the computer, such as to the well-known RJ11 connectors used in business and residential locations for voice telephones. Further, the installation also may involve some additional wiring at the outside of the home or business, that is, where the telephone company's wiring connects to the location (e.g., via a network interface device (“NID”)) as is further explored later. In any event, at the present time an installation of a DSL modem commonly requires a person, such as a telephone company representative, who has a considerable level of technical expertise.
Recalling from above that a DSL modem is typically connected to an RJ11 connector in a home or business, the present embodiments are directed to increasing the chance of proper signal communications when this connection is made. Specifically, an RJ11 connector, as known in the art, includes six cavities aligned in a row, where a conducting pin may be placed within each such cavity; in the majority of home applications, the two outermost of these six cavities are left empty, while the remaining four cavities between those outermost cavities each retain a corresponding conductor pin. Unless stated otherwise, for the sake of a consistent example for the remainder of this document the example of four pins used in the RJ11 connector are described. Thus, in both the RJ11 female receptacle and male plug, these four pins are aligned in a row. The two pins at the ends of the row are referred to in the art as an outer pair, whereas the two pins located along the row and between the outer pair are referred to in the art as the inner pair. Further, a typical voice telephone cable includes two twisted wire pairs of conductors. Often, to support a single telephone line in a home or business and according to the known “plain ordinary telephone service” (“POTS”), one twisted wire pair of the telephone cable is connected to the inner pair pins of the RJ11 connector, while the outer pair pins of the RJ11 connector are not further connected to any conductors of the telephone cable. However, once a DSL modem is contemplated as also being connected to the RJ11 connector, there arises the issue of whether to use the outer pair pins to communicate with the DSL modem, or to further re-arrange the connections to use the inner pair pins to communicate with the DSL modem and then the outer pair pins to communicate with a telephone. Further complicating the possibilities is the fact that filtering is also typically required once a DSL modem is to be supported along with a voice telephone device. By way of further background to these considerations, FIGS. 1 through 3 discussed below depict various contemporary alternative connections of an ADSL modem to an RJ11 connector.
FIG. 1 illustrates a first prior art telephone/DSL modem wiring system designated generally at 10. System 10 includes a twisted wire pair TP1 of conductors provided by the telephone company (“TELCO”) and connected to a network interface device (“NID”) 12. For example, NID 12 is typically enclosed in a box attached to or proximate to the outside of a residential home or business. From NID 12, twisted wire pair TP1 is connected directly to the inner pair of pins IPP1 of an RJ11 receptacle RJ111. Receptacle RJ111 is for connecting to an ADSL modem, that is, an RJ11 plug (not shown) on or connected to an ADSL modem may be inserted within RJ11 receptacle RJ111 to thereby couple the modem to communicate with the TELCO (i.e., with a corresponding modem at the TELCO). Additionally, note that the outer pair of pins OPP1 of RJ11 receptacle RJ111 are electrically floating. Returning to twisted wire pair TP1 in NID 12, it also is connected to an input of a low pass filter (“LPF”) 14, where LPF 14 permits only signals in the POTS frequency to pass, such as those on the order of 4 KHz or less. The output of LPF 14 is connected to the inner pair of pins IPP2 of an RJ11 receptacle RJ112. Receptacle RJ112 is for connecting to a POTS telephone, or other device, such as an answering machine or voice modem, operable to communicate along a POTS medium. Specifically, this connection is typically made by inserting an RJ11 plug (not shown) on or connected to the POTS telephone device into RJ11 receptacle RJ112 to thereby couple the POTS telephone device to communicate with the TELCO. Lastly, note that the outer pair of pins OPP2 of RJ11 receptacle RJ112 are electrically floating.
The operation of system 10 is now explored. In general, the TELCO provides both POTS and DSL modem communications via twisted wire pair TP1 to NID 12. With respect to DSL modem communications, they are achieved via the direct connection to receptacle RJ111. Thus, so long as the ADSL modem is connected to inner pins IPP1 of receptacle RJ111, any appropriate DSL signal may be communicated between the ADSL modem and twisted wire pair TP1. With respect to the POTS communications, they are filtered by LPF 14 and pass to receptacle RJ112. As a result, note that any relatively high frequency signals (i.e., greater than 4 KHz) on twisted wire pair TP1 do not reach receptacle RJ112 and, hence, do not reach any POTS telephone device connected to that receptacle. Such filtering is typically required because current POTS devices do not have a defined frequency response for these relatively high frequency signals. Further, LPF 14 thereby eliminates any possibility that operation of the POTS telephone connected to receptacle RJ112 would then affect the operation of an ADSL modem that is directly-connected to twisted wire pair TP1 via receptacle RJ111. In any event, so long as the POTS telephone device is connected to inner pins IPP2 of receptacle RJ112, any appropriate POTS signal may be communicated between the POTS telephone device and twisted wire pair TP1.
While the preceding discussion of system 10 in FIG. 1 demonstrates a straightforward manner of connecting both an ADSL modem and a POTS telephone device to a TELCO twisted wire pair TP1, various drawbacks also may be observed with respect to system 10. As one drawback, the consumer using system 10 must be aware of the limitation that receptacle RJ111 is for connecting to an ADSL modem and receptacle RJ112 is for connecting to a POTS telephone device. In other words, if the consumer were to reverse these connections, then a POTS telephone device connected to receptacle RJ111 may not properly communicate due to the receipt of relatively high frequency signals, and an ADSL modem connected to receptacle RJ112 would not properly communicate because it would only receive relatively low frequency signals. As another drawback, system 10 operates properly only if both the ADSL modem and the POTS telephone device are configured to communicate along the inner pair of pins of an RJ11 configuration. For a POTS telephone device, this configuration may be likely because many such devices are hard-wired to communicate only along such inner pair pins. However, given the already-expanding competition and development of ADSL technology, some manufacturers may consider providing their ADSL modems with a connection to the outer pair of RJ11 pins rather than the inner pair, such as for reasons further demonstrated below. If such an alternative ADSL modem were connected to receptacle RJ111, then it would not communicate at all given that outer pins OPP1 of receptacle RJ111 are electrically floating.
FIG. 2 illustrates a second prior art telephone/DSL modem wiring system designated generally at 20, and which shares some general aspects with system 10 described above. System 20 includes a twisted wire pair TP2 provided by the TELCO and connected to an NID 22. From NID 22, twisted wire pair TP2 is connected directly to the outer pair of pins OPP3 of an RJ11 receptacle RJ113. For reasons more clear below, RJ11 receptacle RJ113 is for connecting to either an ADSL modem or a POTS telephone device. Additionally, twisted wire pair TP2 in NID 22 is connected to an input of an LPF 24, where LPF 24 operates in the same manner as LPF 14 of FIG. 1, thereby permitting only signals in the POTS frequency to pass. The output of LPF 24 is connected to the inner pair of pins IPP3 of RJ11 receptacle RJ113. Given the preceding connections, note that the connection to inner pair IPP3 and outer pair OPP3 may be achieved using a single POTS cable as shown at CB, thereby including two twisted wire pairs between NID 22 and RJ11 receptacle RJ113.
The operation of system 20 is as follows. The TELCO provides both POTS and DSL modem communications via twisted wire pair TP2 to NID 22. With respect to DSL modem communications, they are achieved via the direct connection from NID 22 to outer pins OPP3 of receptacle RJ113. Thus, an ADSL modem may be connected via an RJ11 plug to receptacle RJ113 and thereby properly communicate ADSL communications with the TELCO so long as the ADSL modem is connected to outer pins OPP3 of receptacle RJ113 rather than to inner pins IPP3 of receptacle RJ113. Conversely, with respect to the POTS communications, they are achieved via the filtered connection to inner pins IPP3 of receptacle RJ113. Thus the POTS telephone device may be connected via an RJ11 plug to RJ11 receptacle RJ113 and may properly communicate POTS communications with the TELCO so long as the POTS telephone device is connected to inner pins IPP3 of receptacle RJ113 rather than to outer pins OPP3 of receptacle RJ113.
While the preceding discussion of system 20 in FIG. 2 demonstrates that system 20 supports either an ADSL modem or a POTS telephone communication from receptacle RJ113, various drawbacks also may be observed with respect to system 20. As one drawback, system 20 operates properly only if the ADSL modem is configured to communicate along the outer pair of pins of an RJ11 configuration and the POTS telephone device is configured to communicate along the inner pair of pins of an RJ11 configuration. Again, given the diverse number of ADSL modems being or to be implemented, there is no assurance that this constraint will be met. As another drawback, for proper operation of both the ADSL modem and the POTS telephone device, system 20 requires that the person who implements its wiring properly terminate each of the four wires at the correct one of either an inner or outer pin; clearly, various reasons may cause an error in such wiring to occur.
FIG. 3 illustrates a third prior art telephone/DSL modem wiring system designated generally at 30. System 30 shares some electrical-connection aspects with system 10 described above while the physical locations of various connections differ in some respects. Turning to system 30, it includes a twisted wire pair TP3 provided by the TELCO and connected to an NID 32. For system 30, however, and as further appreciated below, no additional change is made to NID 32 (e.g., such as a filter) to accommodate an ADSL modem at the home or business corresponding to NID 32. Instead, twisted wire pair TP3 is connected directly to the inner pair IPP4 of pins of an RJ11 receptacle RJ114. In other words, the connection between NID 32 and RJ11 receptacle RJ114 is the same as is typically installed to support standard POTS telephone services. However, to further support both POTS telephone service as well as ADSL communications, system 30 further includes a microfilter 34. Microfilter 34 may be physically presented as a relatively small housing, formed of a rigid material such as plastic, and on the order of two to four inches or less in each of its dimensions. Further, as appreciated from the following description of the electrical connections of microfilter 34, it is configured to be placed in-line between RJ11 receptacle RJ114 and either an ADSL modem or a POTS telephone device.
Looking in detail to the electrical attributes of microfilter 34, it includes an RJ11 plug RJ115 which is physically shaped to be fitted into RJ11 receptacle RJ114 as is known in the art. The inner pins IPP5 of RJ11 plug RJ115 are connected to a twisted wire pair TP4. Twisted wire pair TP4 is connected, within microfilter 34, directly to the outer pair of pins OPP6 of an RJ11 receptacle RJ116. Additionally, twisted wire pair TP4 is connected, within microfilter 34, to the input of an LPF 36, and an output twisted wire pair TP5 from LPF 36 is connected to the inner pair of pins IPP6 of RJ11 receptacle RJ116. Lastly, either an ADSL modem or a POTS telephone device may be connected to RJ11 receptacle RJ116, where such connection may be made by inserting an RJ11 plug (not shown) from either the modem or telephone device into RJ11 receptacle RJ116. To ensure a proper ADSL communication path, the RJ11 plug of the ADSL modem must communicate along its outer pins to contact and communicate with outer pair of pins OPP6 of RJ11 receptacle RJ116. Conversely, to ensure a proper POTS telephone communication path, the RJ11 plug of the POTS telephone device must communicate along its inner pins to contact and communicate with inner pair of pins IPP6 of RJ11 receptacle RJ116. Lastly, while only a single microfilter 34 is shown in system 30, one skilled in the art will recognize that for each RJ11 receptacle wired in the same manner as RJ11 receptacle RJ114, a corresponding microfilter wired in the same manner as microfilter 34 may be connected to the RJ11 receptacle, and in which case either an ADSL modem or a POTS telephone device may be connected to the microfilter in the same manner as described with respect to microfilter 34. In this latter instance of multiple microfilters, note that under contemporary systems only one of those microfilters should connect to an ADSL modem while the remaining microfilters may connect to POTS telephone devices; this arises from the aspect that under contemporary configurations only a single ADSL modem is generally supported for a single copper pair (i.e., at the site of that copper pair), primarily due to the lack of the ability to share frequencies and negotiate a connection between multiple ADSL modems connected at a single copper pair.
While system 30 of FIG. 3 supports both ADSL modem and POTS telephone communications, it too has drawbacks. For example, different types of microfilters may use different sets of inner or outer pins for either ADSL or POTS telephone service and, thus, a modem or telephone device connected to the microfilter must be configured to communicate using the appropriate corresponding pins. As another example, the microfilter represents a separate piece of equipment that the user must obtain.
As yet further background, the prior art further includes some DSL modems which include a mechanical switch typically attached to a circuit board included within the DSL modem. The mechanical switch is intended for use by a technically-savvy person so that such a person may move the switch to one of two positions, where in a first position the DSL modem is connected to communicate along the inner pair of pins of its RJ11 connector while in a second position the DSL modem is connected to communicate along the outer pair of pins of its RJ11 connector. The movement of this switch, however, is purely manual an is not further facilitated by the modem itself; instead, the person operating the switch is somehow left to independently determine the proper location of the switch in an effort to achieve a proper DSL communication path.
In addition to the preceding, the present inventor has recognized additional observations particularly in view of the developing marketplace. For example, given the level of DSL developments, there is also an increasing need to present DSL technology to the general public in as straightforward a manner as possible. Indeed, it is contemplated that consumers will someday seek to implement DSL modems in a manner at least as straightforward as now used for telephone devices and voice modems. Such an approach may bring a consumer to a local electronics store or otherwise permit the consumer to obtain a DSL modem from some alternative source, where the consumer thereafter desires to couple the modem to his or her computer without the assistance of a technically-educated service representative. However, the many alternatives provided above demonstrate that such a consumer is very unlikely to understand the technical considerations involved or necessary to achieve the specific DSL modem connections in their home or office. Also shown above are various factors that may result in an inoperable installation by a consumer. Thus, to facilitate this type of self-installation, there is a need to simplify the process so as to increase the chances that the installation will operate properly, as is achieved by the present embodiments.